Bent tube boiler



LJ.MARSHALL L87l094 BENT TUBE BOILER Filed June 24, 1929 s Sheets-Sheet 1 -1NvENToR' Aug. 16, 1932. L. J. MARSHALL BENT TUBE BOILER 3 Sheets-Sheet 2 Filed June 24, 1929 Q INVENTOIR W 1 WM BY MYS 1932- L. J. MARSHALL 1,872,094

' BENT TUBE BOILER Filed June 24. 1929 5 Sheets-Sheet 3 \rs INVENTOR "@WZ Patented Aug. 16, 1932 UNITED STATES PATENT OFFICE LEONARD J. MARSHALL, OF LEONIA, NEW JERSEY, ASSIGNOB. TO INTERNATIONAL COMBUSTION ENGINEERING CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE BENT TUBE BOII ER Application filed June 24, 1929. Serial No. 373,226.

This invention relates to improvements in bent tube boilers of the type having upper steam and Water drums, a lower mud drum and banks of tubes connecting the drums.

One of the primary objectsof my invention is the provision of a boiler of the above type having large effective steam space, libcrating surface and water storage and one which is capable of high output with small fluctuations in Water, level.

Another object of my invention is the provision of improvements in the arrangement of the tubes of the banks of boiler tubes connecting the drums whereby very effective circulation is obtained.

A further object of my invention is the provision of a boiler of the type above mentioned in which the arrangement of boiler tubes is suchthat increased ligament efliciency is obtained, thus making it possible to employ, with safety, comparatively thin Walled, relatively inexpensive, upper drums of large diameter for high pressures.

A more specific object of my invention is the provision of a boiler of the type including a lower drum, a pair of upper drums and banks of upright connecting tubes in which substantially one-half of the tubes of each bank are connected into one upper drum and the remaining tubes into the other upper drum.

How the foregoing, together with such other ob ects and advantages as may hereinafter appear, or are incident to my invention,

are realized is illustrated in preferred form in the accompanying drawings, wherein- Fig. 1 is a vertical section through a boiler embodying my improvements.

Fig. 2 is a fragmentary plan section taken on the line 2-2 of Fig. 1.

Fig. 3 is a. vertical section through the upper portion of a modified boiler.

Fig. 4 is a fragmentary elevation showing another modification of the invention.

Figs. 5 and 6 are diagrammatic elevational views of still other modifications of the invention.

Fig. 7 illustrates a-modified arrangement of the upper drums and certain of the tubes.

Fig. 8 is a fragmentary section taken on the line 88 of'Fig. 7.

Referring now more particularly to Figs. 1 and 2, the boiler comprises in general a lower transverse mud drum 7, a pair of transverse upper steam and water drums 8 and 9, a front bank of'connecting boiler tubes 10, a second bank of connecting boiler tubes 11, a transverse rear or dry drum 12, and a rear bank of boiler tubes 13.

The tubes of the banks are arranged in parallel spacing, and referring now to the front bank of tubes 10, it will be seen that the tubes thereof are arranged in a plurality of spaced rows extending in a plane perpendicular to the axes of the drums and that I preferably connect the tubes of every other complete row from the mud drum 7 to the front upper drum 8 and the tubes of the other rows from the mud drum to the second upper drum 9. Stated in another way, the first complete row of tubes in a plane perpendicular to the axes of the drums connects the lower drum 7 tothe front upper drum 8, the next complete row in a parallel plane connects the lower drum 7 to the second upper drum 9, the next 'row in a parallel plane connects the lower drum 7 to the front upper drum 8 and so on for the entire width of the bank of tubes.

The tubes of the second bank 11 are arranged in a manner similar to those of the first bank, that is to say, the first row of tubes connects the mud drum 7 and the front upper drum 8, the second row connects the mud drum 7 to the second upner drum 9 and so on for the entire width of the bank. It is pointed out that the rows of the first bank 10 are aligned with the rows .of the second bank 11 and that the tubes of the rows of the first bank which connect the mud drum to the second upper drum cross the tubes of the rows of the second bank which connect the mud drum to the first upper drum, the crossing of the tubes being in the upper portion of the boiler.

It will thus be seen that substantially onenect into the front upper drum, while the remaining tubes of each of the banks connect into the second upper drum.

The pointsof connection of the tubes into the upper steam and water drums are arranged in circumferential rows and inasmuch as only every other row is connected to one drum with the remaining rows connected to the other drum, these circumferential rows will be relatively widely spaced apart, thus giving increased ligament efiiciency and enabling me to employ comparatively thin walled upper drums of large diameter for high pressures. The cost of such large thin walled drums is very considerably less than the cost of thick walled drums which would have to be employed for high pressures in'the absence of my improvements. The fastening of the tubes in thick Walled drums is also an expensive operation.

The large drums which I employ also pro- Vide large effective steam space, liberating surface, and water storage.

The arrangement and spacing of the tube Each of the upper steam and water drums.

8 and 9 are provided with steam outlets and in the form shown in Fig. 1 steam isled from the steam space of the drum 8 to the rear. dry drum 12 by means of a plurality of steam circulating tubes 14 and from the drum 9 to the drum 12 by means of a plurality of steam circulating tubes 15. The rear drum 12 is provided with a steam outlet 16. A plurality of water circulators 12a connect the water spacesof the drums 9 and 12. Feed water may be admitted into the rear drum 12 of the boiler by means of a pipe 126.

A boiler constructed in accordance with my invention is capable of high output with small fluctuations in water level and consequently dry steam is obtained. The arrangement and connections of the tubes is such that the water level in the drums 8 and 9 would'be practically the same at all ratings.

A combustion chamber A is located in front of and beneath the boiler and the boiler is bafiled as indicated at 17, 18 and 19, so that the gases of combustion pass upwardly of the front bank 10, then. pass to the second bank, then pass downwardly of the second bank 11, and finally pass upwardly of the rear bank 13 to the outlet 20.

By providing a direct connection from the front steam and water drum 8 to the mud drum 7 through tubes of the middle bank 11 where generation of steam is not as active as in the front bank 10, much better natural circulation is obtained than inarrangements where the water separated from the steam liberated in the steam drum must either return to the mud drum through circulator tubes connected to an adjacent steam drum and then through a middle bank of tubes to the mud drum, or where the water must pass directly down thru tubes of the front bank Where steam generation is rapid. In either case, the circulation is restricted, the water level in the front drum being too high and the steam-water ratio in the upcomer tubes reaching a value which might be dangerous. The cross-over tubes provide useful heating surface for the return circuit of the front tube bank. The advantages just above pointed out are also derived in connection with the second drum 9 for the tubes connecting the mud drum to the drum 9 are also divided between the first and second banks as has been fully pointed out hereinbefore.

In Fig. 3 I have illustrated a modified arrangement in which three banks of tubes 21, 22 and 23 are provided for connecting the lower mud drum to the upper steam andwater drums 8a and 9a. The first and second banks of tubes 21 and 22 are each composed of a plurality of rows of tubes extending in a plane perpendicular to the axes of the drums. Every other row of each of these banks is connected from the mud drum to the upper drum 9a and the remaining rows are connected into the other upper drum 8a. The third bank 23 is similar to the first and second banks in that every other row connects from the mud drum to the upper drum 9a, while the remaining rows connect from the mud drum to the upper drum 8a. Suitable bafiling 24 is provided to cause the gases to flow upwardly of the first bank, downwardly of the second bank and upwardly of the third bank.

The circulation in the boiler tubes is upward in the rows of tubes 21a, 21b, and upward or downward in the rows 22b and 22a and downward in the rows of tubes 23a and 236.

Each of the upper drums is provided with a steam outlet 25 from which steam may be led by means of piping 26.

The points of connection of the tubes of the various rows connecting into the upper drums are aligned circumferentially, thereby providing a plurality of spaced circumferential rows.

In Fig. 4 I have illustrated another modification in which a number of the tubes of the front bank are connected into the upper drums above the water line as indicated at 27. This correspondingly lowers the point of connection of the rear or downcomer tubes The form shown in Fig. 5, insofar as to the arrangement of the lower drum 7?), the upper drums 8b and 9b and the banks of connecting tubes, is the same as that illustrated in Fig. 3. However, the steam is led from the upper drums 8b and 9?) into a third or dry drum 29 by means of pipes 30 and 31. Feed water may be introduced into the drum 29 and led to the lower drum 7 b by means of a plurality of rows of tubes 32.

In Fig. 6 I have arranged a dry drum 33 above and between the upper boiler drums 8b and 9b to which steam is led by means of pipes 34.

In Fig. 7 I have shown an arrangement in which the front and rear; upper drums 8c and 120 are located at the same level and in which the middle upper drum 9c is located somewhat below the level of the other two upper drums.

In this form the tubes 14a connecting the steam spaces of the front and rear drums are secured at the rear drum in a row of tube holes which are spaced circumferentially from a row of tube holes in which the tubes 15a connecting the steam spaces of the middle and rear drums are connected. Thus I provide ample ligament strength for high pressure. It is also to be noted that the upper end portions of the tubes 13?) of the tubes of every other row of the rear bank 13a are bent so as to be connected into the rear drum 120 at points circumferentially spaced from i the points of connection of the tubes ofthe other rows of said bank. This provides for greater ligament strength at the points of connection of the tubes of the rear bank, The arrangement of tube connections for the tubes 14a and 15a and the tubes of the bank 13a provides for a spacing in the rows of tube holes extending longitudinally of the drum which may be at least twice the spacing of the tubes of the bank crosswise of the boiler.

I claim: i

1. A water tube boiler including a pair of upper steam and water drums, a lower mud. drum, and banks of boiler tubes connecting the mud drum to said upper drums, each bank comprising a plurality of spaced rows of tubes extending in a plane perpendicular to the axes of the drums, alternate rows of" which connect the mud drum to one of the upper drums and the remaining rows of.

which, connect the mud drum to the other upper drum.

2. A water tube boiler including a lower mud drum, three upper steam and water drums, and three banks of boiler tubes connecting the mud drum and the upper drums,

the tubes of said banks being arranged in spaced rows extending in planes perpendicular to the axes of the drums, the first bank having certain rows of its tubes connecting the mud drum and the first upper drum and the remainder of its rows of tubes connecting the mud drum and the second upper drum, the second bank having certain of its rows of tubes connecting the mud drum and the second upper drum and the remainder of its rows of tubes connecting the mud drum and the first upper drum, and the third bank having its rows of tubes connecting the mud drum and the third upper drum, together with means connecting the steam spaces of the first and third upper drums and means connecting the steam spaces of the second and third upper drums.

3. A water tube boiler, including a pair of upper transverse steam and water drums, a

lower mud drum, and three banks of boiler tubes, the tubes of said banks being arranged in spaced rows extending in planes perpendicular to the axes of the drums, the lower ends of the tubes of said banks being connected into the mud drum, and the upper ends of substantially one-half of the rows of tubes of each bank being connected into one of the upper drums and the upper ends of the remaining rows of tubes of each bank being connected into the other upper drum.

4. A water tube boiler, including a pair of upper transverse steam and water drums, a lower mud drum, and three banks of boiler tubes, the tubes of said banks being arranged .in spaced rows extending in planes perpendicular to the axes of the drums, the lower ends of the tubes of said banks being connected into the mud drum, and the upper ends of substantially one-half of the rows of tubes of each bank being connected into one of the upper drums and the upper ends of the remaining rows of tubes of each bank being connected into the other upper drum, together with an upper steam drum, and means connecting the steam spaces of said upper steam and water drums to said steam drum. 5. A Water tube boiler, including a pair of upper transverse steam and water drums, a lower mud drum, and three banks of boiler tubes, the tubes of said banks being arranged in spaced rows extending in planes perpendicular to the axes of the drums, the lower ends of the tubes of said banks being connected into the mud drum, and the upper ends of substantially one-half of the tubes of each bank being connected into one of the upper drgms and the upper ends of the remaining tu es of each bank being connected into the rows extending in planes perpendicular to the axes of the drums and With the correspondin g rows of the banks in the same plane, and the tubes ofevery other row of the banks being connected at their upper ends into one of said tWo upper drums and the other tubes of the remaining rows being connected at their upper ends into the other of said two upper drums, and another bank of boiler tubes connecting the mud drum to a third upper drum.

7. A water tube boiler, including a lower transverse mud drum, a plurality of upper transverse steam and Water drums, and a plurality of banks of boiler tubes connecting the mud drum to the upper drums, the tubes of said banks being arranged in spaced roWs extending in planes perpendicular to the axes of the drums and with the corresponding rows of the banks in the same plane, and the tubes of every other row of the banks being connected at their upper ends into one upper drum and the other tubes of the remainin g rows being connected at their upper ends into one other upper drum, the points of connect on into said upper drums being arranged in a plurality of circumferential rows, and each drum having half as many rows as there are rows of tubes in each bank.

8. In combination, a bent tube boiler having a pair of relatively largethin Walled transverse steam and Water drums, a transverse inud drum and connecting banks of tubes, the tubes of the banks being arranged in aligned rows in planes perpendicular to the axes of the drums, and the tubes of every other aligned row being connected at their LEONARD J. MARSHALL.

upper'ends into one of the upper drums and the tubes of the remaining aligned rows being connected at their upper ends into the other of the upper drums, each upper drum being provided with a plurality of relatively widely spaced circumferential rows of tube receiving openings, one row for each of the aligned rows of tubes to be connected thereinto.

9. A water tube boiler including a lower mud drum, three upper steam and water drums, and three banks of boiler tubes connecting the mud drum and the upper drums, the tubes of said banks being arranged in spaced rows extending in planes perpendicular to the axes of the drums, the first bank having certain of its rows of tubes connecting the mud drum and the first upper drum and the remainder of its rows of tubes connecting the mud drum and the second upper drum, the second bank havingcertain of its' rows of tubes connecting the mud drum and the second upper drum and the remainder of its rows of tubes connecting the mud drum and the first upper drum, and the third bank having its tubes connecting the mud drum and the third upper drum with the tubes oi every other row being connected into the th1rd upper drum at points circumferentially 

